Modern vehicle sound systems include speakers disposed at strategic locations within the vehicle. A host amplifier that receives an audio signal from a head unit, such as a CD player, a radio, or other audio source, drives these speakers.
Many vehicle sound systems also include a subwoofer specifically to provide bass. This subwoofer draws on considerably more power than the other speakers. As a result, in many vehicle sound systems, the subwoofer has its own separate amplifier, often called the “satellite amplifier.”
Components of vehicle sound systems often include diagnostic subsystems. These diagnostic subsystems enable a component to communicate its operating condition to another component. This allows that other component to compensate, or adjust its own operation accordingly. In typical applications, a satellite amplifier will communicate its operating condition to the host amplifier that drives it.
Although it is straightforward for an amplifier to receive diagnostic information from those speakers that it drives, it is far more difficult to receive diagnostic information from speakers other than those that it directly drives. In particular, in a multi-amplifier sound system, a difficulty can arise in communicating diagnostic information from the satellite amplifier to the host amplifier.